Electrode assembly



March 5, 1940.

F. KASPAR 2,192,551

ELECTRODE ASSEMBLY Filed Qt-i1 2, 1938 Patented Mar. 5, 1940 UiT STATES ELECTRODE ASSEMBLY Frank Kaspar, Cicero,

111., assignor to General Scientific Corporation, Chicago, 111., a corporation of Illinois Application April 2, 1938, Serial No. 199,596

2 Claims.

The present invention relates to gaseous conduction tubes such as are used in the well-known neon sign advertising displays. This invention is particularly directed to an electrode assembly 5 for such devices and has as its principal object the provision of a supporting assembly by which an electrode may be positioned centrally of the tube and held in this position.

In the processing of the tubes, and particularly 10 during the bombardment of the electrode and the tube interior, the electrode becomes quite hot and there is danger of breaking the tube if the support gives way and allows the hot electrode 'to fall over against the tube. The present inven- 5 tion contemplates an electrode assembly and method whereby the electrodewhenflnallysecured in the tube is firmly held in a centralized position with respect to the tube.

I will describe the preferred form of the inven- 20 tion by reference to the accompanying drawing wherein:

Fig. 1 is a view illustrating the initial step in preparing the electrode assembly;

Fig. 2 is a view in longitudinal section through 25 an electrode and its supporting collar illustrating a second step in the assembly;

Fig. 3 is a view like Fig. 2 illustrating a third step in the assembly, and

Fig. 4 is a view partly in section and partly in side elevation illustrating the final assembly of the electrode within a tube.

Referring now to the drawing, the numeral 5 designates an electrode which is of the cylindrical type and which is composed of a suitable 35 metal. This electrode is provided with a substantially conical end portion 6 that is closed upon a lead-in wire I by any suitable method such as by the crimp 8 in the metal at the end of the electrode. Numeral 9 refers to a glass tube which 40 is utilized in the electrode assembly and is provided with a flared portion In to receive the conical portion 6 of the electrode 5. The entire electrode assembly is to be mounted in a gaseous conduction tube l I, as will be readily understood.

In preparing the electrode assembly I first provide a tube 9 with the flared end II] in the manner shown in Fig. 1 where a burner P2 is used to heat and soften the end of the tube 9, and a pointed tool is is applied to form the conical portion I0. 50 It will be noted that the shape of the conical portion I0 is such that when the electrode 5 is seated therein, as shown in Fig. 2, it rests near the tip of the conical portion Ill which provides adequate support adjacent the widest part of the 55 conical surface 6 of the electrode.

The lead-in wire 1 is attached to the electrode 5 before the electrode is heated in the tube 9. This lead-in wire is of a type that has been treated so that it can be readily seated in glass.

For example, I use iron wire having a copper borate coating known in the trade as Dumet. With the electrode seated in the conical portion In, and the lead-in wire I drawn down to hold it firmly in place, the glass tube 9 is next heated and sealed onto the lead-in wire at M, as shown in Fig. 3. The portion of the lead-in wire shown at H) between the seal M and the end of the electrode serves to hold the electrode in seated position in the conical part ID of the glass tube 9. The space between the electrode and the conical portion 9 serves to provide mean free path insulation which protects the lead-in wire portion l5 from the discharge which takes place within the tube. When the electrode assembly is completed, as shown in Fig. 3, it may then be mounted in a tube ll, as shown in Fig. l, by sealing the part It and the lead-in wire 1 to the base l6 of the tube H.

From the foregoing description it, is believed that the advantages of the present invention and the manner in which it is carried out will be readily apparent to those skilled in this art. I It is also believed to be obvious that various minor modifications may be made without departing from the scope of the invention as expressed in the claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An electrode assembly for gaseous conduction tubes comprising a cylindrical electrode having a closed end including a tapered portion, a lead-in wire projecting from the closed end of the electrode, a supporting sleeve having a flared end receiving the tapered portion of the electrode and providing a seat therefor, said sleeve and lead-in wire being spaced apart at the end of the electrode and sealed together at a distance from the end of the electrode whereby to hold the electrode seated in said sleeve.

2. An electrode assembly for gaseous conduction tubes comprising a cylindrical electrode having a closed end including a tapered portion, a lead-in wire projecting from the closed end of the electrode, a supporting sleeve having a flared end receiving the tapered portion of the electrode and providing a seat therefor, said sleeve and lead-in wire being spaced apart at the end of the electrode and sealed together at a distance from the end of the electrode whereby to hold the electrode seated in said sleeve, said electrode being tapered FRANK when. 

